Are you confident there is a complete insignificant number of teamster members that have no racial biases at all? And that they all believe women as just as capable leaders?

I strongly suspect that a very high percentage of the members that would flip when their candidate turns out to be a woman and/or minority were already solidly in the Trump camp even when Biden was running. I really do not believe that 40% of the teamsters currently in favor of Trump preferred another option before the democratic candidate was changed to a minority woman.

Not identical, but I don't think I've encountered anyone IRL who thinks more highly of Biden than of Obama without loathing Biden.